The principal investigator has recently discovered a novel phenomenon that produces high ion currents when compounds containing metal atoms are introduced into a flame. The phenomenon was developed into a gas chromatographic detector that is 1000 times more sensitive for organometallics than a standard flame ionization detector and has a selectivity factor for these compounds over hydrocarbons greater than 10,000. The flame, when optimized for response, including that of toxic heavy metals burns in a hydrogen atmosphere that has been doped with a small amount of silane. Conversely, the principal investigator has demonstrated that if the hydrogen atmosphere is doped with a metal-containing compound rather than silane, the flame responds to compounds containing silicon. No detector presently exists which is specific for silicon-containing compounds. Standard methods for gas chromatographic analysis of many biologically important molecules such as amino acids, sugars, steroids, hydroxyfatty acids, etc., involve the formation, separation and detection of silyl derivatives. The development of a sensitive and selective detector for biomolecules tagged with silicon will extend the scope of the silylation technique to permit trace analysis of compounds of interest in complex biological matrixes. These methods can be readily adapted and automated for many clinical assays. By changing certain crucial parameters this detector may be made sensitive to compounds other than those containing metals or silicon. Potentials for selective detection of compounds containing selenium or arsenic have been demonstrated. Furthermore, due to this detector's tremendous discrimination against hydrocarbon compounds, its application may be successfully extended to liquid chromatography effluents. This proposal delineates more extensive studies into the metal selective response, procedures for the development, optimization, and application of the silicon selective response and investigations into several other promising modes of operation of this hydrogen atmosphere flame ionization response.